An important technique for the construction of silver halide light-sensitive materials is one in which an inherently mobile photographically useful compound is combined with a compound provided with nondiffusibility to fix itself to specified portions on a support, and then undergoes a chemical reaction with reacting agents and reaction initiators which have been externally supplied upon processing to release a photographically useful compound. In particular, functional redox compounds which undergo a reaction triggered by an oxidation or reduction reaction upon processing to release a photographically useful compound can be expected to exert various effects which cannot be attained with other precursors. For example, the use of a functional redox compound which releases a dye can give a design in which an oxidation or reduction reaction takes place in correspondence to or counter correspondence to the exposure of silver halide to obtain color images. Among these functional redox compounds, compounds which undergo reduction to release a photographically useful compound are advantageous in that they are fairly stable and can easily provide positive images in counter correspondence to the exposure of silver halide and have thus been extensively studied.
Examples of functional redox compounds which undergo reduction to release a photographically useful compound include compounds which undergo an intramolecular nucleophilic reaction after reduction to release a photographically useful compound as disclosed in U.S. Pat. Nos. 4,139,379, 4,139,389, and 4,564,577, and JP-A-59-185333 and JP-A-57-84453 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), and compounds which undergo an intramolecular electron transfer reaction after reduction to release a photographically useful compound as disclosed in U.S. Pat. No. 4,232,107, JP-A-59-101649, and JP-A-61-88257, and Research Disclosure (1984) IV No. 24025.
Examples of compounds which utilize cleavage of specific bonds by reduction include compounds which utilize reduction cleavage of a nitrogen-sulfur bond as disclosed in German Patent 3,008,588, and JP-A-62-244048, compounds which utilize a nitrogen-nitrogen bond as disclosed in U.S. Patent 4,619,884, .alpha.-nitro compounds which undergo cleavage of a carbon-hetero atom single bond after receiving electrons as disclosed in German Patent 3,207,583, and dieminal dinitro compounds which undergo .beta.-elimination of a photographically useful group after reduction cleavage of a nitrogen-nitrogen (nitro group) bond as disclosed in U.S. Pat. No. 4,609,610. Examples of compounds which utilize reduction cleavage of a carbon-hetero atom single bond include newly developed compounds as disclosed in JP-A-62-215270 and European Patent 220746A2.
Further, in recent years, as positive-working redox compounds which can attain both excellent stability and processing activity, compounds have been developed as disclosed in JP-A-62-215270 and European Patent 220746A2.
The foregoing functional redox compounds which undergo reduction to release a photographically useful group have their advantages. However, it is desirable to provide a new means of releasing a photographically useful group in order to enhance its functions corresponding to the purpose or enhance the degree of freedom of design in the preparation of photographic light-sensitive materials. cl SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a silver halide photographic material comprising a truly novel compound which undergoes reaction with a reducing substance (a reducing agent) commonly used in the art to release a photographically useful group at an extremely high rate.
The above and other objects of the present invention will become more apparent from the following detailed description and examples.
The inventors have studied the cleavage reaction of a nitrogen-oxygen single bond on the basis of the technique as disclosed in JP-A-62-215270. As a result, it was found that a nitrogen-oxygen single bond connected to an electron-accepting group on its oxygen side undergoes an extremely rapid cleavage after receiving electrons. It was also found that this reaction proceeds at a sufficiently high rate even under neutral conditions. The object of the present invention is accomplished by the use of a silver halide photographic material which comprises a compound containing a nitrogen-oxygen single bond represented by general formula (I): ##STR3## wherein EAG represents an electron-accepting group; A represents a group which undergoes a reaction triggered by the cleavage of the oxygen-nitrogen single bond in general formula to release PUG; B represents a hydrogen atom or an alkyl group, an aralkyl group, an aryl group, a heterocylic group, an acyl group, a sulfonyl group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxysulfonyl group or an aryloxysulfonyl group which may contain substituents; the solid line indicates a single bond; the broken line indicates that either of these lines is a bond, with the proviso that when the broken line between N and A represents a bond, B is not present; EAG and B, and A and B may be connected to each other to form a ring; EAG may be connected to a polymer residue to fix the compound of general formula (I) to a high molecular chain; n represents an integer 0 or 1; and PUG represents a photographically useful group, with the proviso that when n is 0, PUG represents a photographically useful group represented by general formula (II): ##STR4## wherein X and Y each represents an atom or atomic group required to render the group represented by general formula (II) photographically useful; the solid lines indicate a single bond; and the broken lines indicate that either of these lines is a bond, with the proviso that X and Y may be connected to each other to form a heterocyclic group containing N and when the broken line between N and X represents a bond, Y is not present.
The mechanism by which the compound represented by general formula (I) undergoes a reaction with a reducing substance to release a photographically useful group is not yet known in detail. However, the inventors believe that the compounds of the present invention can be roughly divided into two groups: (a) those having a structure such that the electron-accepting portion (EAG) which receives two electrons from a reducing substance and (b) those having a structure such that the EAG receives one electron from the reducing substance.
In the structure (a), as a result of the reception of two electrons, the electron-accepting portion is reduced. Then, a rapid intramolecular electron transfer takes place so that an electron moves to the nitrogen atom in the nitrogen-oxygen bond cleaved from the electron-accepting portion in the reduced form. As a result, the compounds of general formula (I) wherein n is 0 release a photographically useful group represented by general formula (II), and the compounds of general formula (I) wherein n is 1 undergo a subsequent reaction to release a photographically useful group.
In the structure (b), the electron-accepting portion receives one electron to become an anion radical while the reducing substance becomes a one-electron oxidant. This reaction is believed to achieve equillibrium. However, the cleavage of the nitrogen-oxygen bond from the anion radical intermediate takes place irreversibly to release a photographically useful group.
The compound represented by general formula (I) will be further described hereinafter. EAG will be described first.
EAG represents a group which receives electrons from a reducing substance and is connected to an oxygen atom. Preferred examples of groups as EAG include quinones (e.g., quinones which may be substituted, such as 1,4-benzoquinone-2-il, 1,4-naphthoquinone-2-il, 3,5,6-trimethyl-1,4-benzoquinone-2-il, 5-benzoylamino-1,4-benzoquinone-2-il, 5-t-octyl-1,4-benzoquinone-2-il, 3-carbamoyl-6-pentadecyl-1,4-benzoquinone-2-il, 1,2-benzoquinone-4-il, 1,2-naphthoquinone-4-il, -hexadecyloxy-1,2-benzoquinone-4-il), aryl groups substituted by at least one electrophilic group (e.g., 4nitrophenyl, 2-nitrophenyl, 2-nitro-4-N-methyl-Noctadecylsulfamoylphenyl, 2-N,N-dimethylsulfamoyl-4nitrophenyl, 2-cyano-4-octadecylsulfonylphenyl, -nitro-4-N-methyl-N-hexadecylcarbamoylphenyl, 2,4-dimethanesulfonyl, 2,4-dinitrophenyl, 2,4,6- tricyanophenyl, 2,4-dinitronaphthyl, 2,3,4,5,6-pentafluorophenyl, 2-nitro-4-trifluoromethyl phenyl, 2-chloro-4-nitro-5-methylphenyl), substituted or unsubstituted heterocyclic groups (e.g., 2-pyridyl, 2-pyradyl, 5-nitro-2-pyridyl, 5-N-hexadecylcarbomoyl-2-pyridyl, 5-dodecylsulfonyl-2-pyridyl, 5-cyano-2-pyradyl, 4-nitrothiophene-2-il, 5-nitro-1,2-dimethylimidazole-4-il, 3,5-diacetyl-2-pyridyl, 1-methylpyridinium-2-il, 1-benzyl-5-carbamoylpyridinium-2-il, 1-methylpyridinium-4-il, 1-dodecylpyridinium-4-il, 1-methyl-3-carboethoxy-5-N-octadecylcarbamoylpyridinium-2-il), quinone analogues having by the following structures (* indicates the portion to be connected to an oxygen atom): ##STR5## and vinylogs thereof. The term "vinylog" as used herein means that the above-exemplified groups as EAG may be bound to the oxygen atom in general formula (I) through a unsaturated bond such as a double bond or a triple bond.
EAG may be connected to a polymer residue, however, it is preferred that the EAG is not connected to a polymer residue.
The term "a polymer residue" means a group present on the terminal of a polymer. That is, EAG may be connected to a polymer through the polymer residue. Examples of the polymer residue to which the EAG may be connected include an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkynyl group, an acyl group, a sulfonyl group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyloxy group, a sulfonyloxy group, an acylamino group or a sulfonylamino group. Examples of the polymer include acrylic esters, metacrylic esters and acrylic amides.
The group represented by A undergoes a reaction triggered by the cleavage of the oxygen-nitrogen bond caused by the reception of electrons by EAG to release a photographically useful group. Preferred examples of the group represented by A include those represented by general formulae (A-1) to (A-7) wherein (*)(*) indicates the position at which the compound is connected to a nitrogen atom; and (*)(*)(*) indicates the position at which the compound is connected to PUG: ##STR6## wherein G.sub.1 represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, a heterocyclic group, --OR.sup.1, --SR.sup.1, --O.sub.2 C--R.sup.1, --O.sub.3 S--R.sup.1, --NR.sup.2 R.sup.2, --NR.sup.2 OC-R.sup.1, --NR.sup.2 O.sub.2 S--R.sup.1, --CO.sub.2 R.sup.1, --CONR.sup.1 R.sup.2, --SO.sub.2 NR.sup.1 R.sup.2, --COR.sup.1, --SO.sub.2 R.sup.1, a halogen atom, a cyano group, or a nitro group; R.sup.1 and R.sup.2 may be the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group or a heterocyclic group; and q represents an integer from 1 to 4, with the proviso that when q is 2 or more, the substituents represented by G.sub.1 may be the same or different or the G.sub.1 groups may be connected to each other to form a ring; ##STR7## wherein G.sub.1 and q are as defined in general formula (A-1); ##STR8## wherein G.sub.2 represents an atomic group required to form a 5- to 7-membered heterocyclic group comprising at least one atom selected from the group consisting of carbon, nitrogen, oxygen and sulfur, the heterocyclic group optionally being condensed with benzene ring, another heterocyclic group, etc. (preferred examples of such a heterocyclic group include pyrrole, pyrazole, imidazole, triazole, furan, oxazole, thiophene, thiazole, pyridine, pyridazine, pyrimidine, pyrazine, azepine, oxepine, indole, and benzofuranquinoline); and G.sub.1 and q are as defined in general formula (A-1); ##STR9## wherein G.sub.3 represents an atomic group required to form a 5- to 7-membered heterocyclic group comprising at least one compound selected from the group consisting of carbon, nitrogen, oxygen and sulfur; and G.sub.4 and G.sub.5 each represents --C(R.sub.3).dbd. or --N.dbd. in which R.sub.3 represents a hydrogen atom, an alkyl group or an aryl group, the heterocyclic group optionally being condensed with benzene ring or 5- to 7- membered heterocyclic group (preferred examples of such a heterocyclic group include pyrrole, imidazole, triazole, furan, oxazole, oxadiazole, thiophene, thiazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, azepine, oxepine, and isoquinoline); ##STR10## wherein G.sub.6 represents an oxygen atom or a sulfur atom; ##STR11## wherein G.sub.7 represents a hydrogen atom or an alkyl, aralkyl, aryl, alkoxy, alkylthio, aryloxy, arylthio, amino, carbonylamino or heterocyclic group which may be substituted.
The group represented by B is connected to a nitrogen atom and represents a group selected to adjust the reactivity and stability of the compound represented by general formula (I). Preferred examples of the group represented by B include a hydrogen atom, an alkyl group, an aralkyl group (e.g., the alkyl group which may be substituted, such as methyl, trifluoromethyl, benzyl, chloromethyl, dimethylaminomethyl, ethoxycarbonylmethyl, aminomethyl, acetylaminomethyl, ethyl, carboxyethyl, allyl, 3,3,3-trichloropropyl, n-propyl, iso-propyl, n-benzyl, iso-butyl, sec-butyl, t-butyl, n-benzyl, sec-pentyl, t-pentyl, cyclopentyl, n-hexyl, sec-hexyl, t-hexyl, cyclohexyl, n- octyl, sec-octyl, t-octyl, n-decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, sec-hexadecyl, t-hexadecyl, n-octadecyl, and t-octadecyl), an alkenyl group (e.g., alkenyl group which may be substituted, such as vinyl, 2-chlorovinyl, 1-methylvinyl, 2-cyanovinyl, and cyclohexene-1-il}, an alkynyl group (e.g., alkynyl group which may be substituted, such as ethynyl, 1-propynyl, and 2-ethoxycarbonyl ethynyl), an aryl group (e.g., aryl group which may be substituted, such as phenyl, naphthyl, 3-hydroxyphenyl, 3-chlorophenyl, 4-acetylaminophenyl, 2-methanesulfonyl-4-nitrophenyl, 3-nitrophenyl, 4-methoxyphenyl, 4-acetylaminophenyl, 4-methanesulfonylphenyl, and 2,4-dimethylphenyl), a heterocyclic group (e.g., heterocyclic group which may be substituted, such as 1-imidazolyl, 2-furyl, 2-pyridy1,5-nitro-2-pyridy1,3-pyridy1,3,5-dicyano-2-pyridyl, 5-tetrazolyl, 5-phenyl-1-tetrazolyl, 2-benzthiazolyl, 2-benzimidazlyl, 2-benzoxazolyl, 2-oxazoline-2-il, and morpholino), an acyl group (e.g., acyl group which may be substituted, such as acetyl, propionyl, butyloyl, iso-butyloyl, 2,2-dimethylpropionyl, benzoyl, 3,4-dichlorobenzoyl, 3-acetylamino-4-methoxybenzoyl, 4-methylbenzoyl, and 4-methoxy-3-sulfobenzoyl), a sulfonyl group (e.g., sulfonyl group which may be substituted, such as methanesulfonyl, ethanesulfonyl, chloromethanesulfonyl, propanesulfonyl, butanesulfonyl, benzenesulfonyl, and 4-toluenesulfonyl), a carbamoyl group (e.g., carbamoyl group which may be substituted, such as carbamoyl, methylcarbamoyl, dimethylcarbamoyl, bis-(2-methoxyethyl)carbamoyl, and diethylcarbamoyl, cyclohexylcarbamoyl), a sulfamoyl group (e.g., sulfamoyl group which may be substituted, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, diethylsulfamoyl, bis-(2-methoxy)sulfamoyl, di-n-butylsulfamoyl, 3-ethoxypropylmethylsulfamoyl, and N-phenyl-N-methylsuylfamoyl), an alkoxy or aryloxycarbonyl group (e.g., alkoxy or aryloxycarbonyl group which may be substituted, such as methoxycarbonyl, ethoxycarbonyl, phenoxycarbonyl, and 2-methoxyethoxycarbonyl), and an alkoxy or an aryloxysulfonyl group (e.g., alkoxy or aryloxysulfonyl group which may be substituted, such as methoxysulfonyl, ethoxysulfonyl, phenoxysulfonyl, and 2-methoxyethoxysulfonyl).
PUG represents a photographically useful group.
Examples of such a photographically useful group include a development inhibitor, a development accelerator, a nucleating agent, a coupler, a diffusive or nondiffusive dye, a desilvering accelerator, a desilvering inhibitor, a silver halide solvent, a competitive compound, a developing agent, an auxiliary developing agent, a fixation accelerator, a fixation inhibitor, an image stabilizer, a toner, a processing dependence improver, a halftone improver, a dye image stabilizer, a photographic dye, a surface active agent, a film hardener, a desensitizer, a contrast developer, a chelating agent, a fluorescent brightening agent, a filter dye (a dye for a filter) and precursors thereof.
Many of these photographically useful groups overlap each other with respect to their utility. Typical examples of these photographically useful groups will be further described hereinafter.
Examples of development inhibitors include compounds containing a mercapto group connected to a heterocyclic group such as substituted or unsubstituted mercaptoazoles (e.g., 1-phenyl-5-mercaptotetrazole, 1-(4-carboxyphenyl)-5-mercaptotetrazole, 1-(3-hydroxyphenyl)-5-mercaptotetrazole, 1-(4-sulfophenyl)-5-mercaptotetrazole, 1-(3-sulfophenyl)-5-mercaptotetrazole, 1-(4-sulfamoylphenyl)-5-mercaptotetrazole, 1-(3-hexanoylaminophenyl)-5-mercaptotetrazole, 1-ethyl-5-mercaptotetrazole, 1-(2-carboxyethyl)-5-mercaptotetrazole, 2-methylthio-5-mercapto-1,3,4-thiadiazole, 2-(2carboxyethylthio)-5-mercapto-1,3,4-thiadiazole, 3-methyl-4-phenyl-5-mercapto-1,2,4-triazole, 2-(2-dimethylaminoethylthio) 3-methyl-4phenyl-5-mercapto-1,2,4-thriazole, 2-(2-dimethylaminoethylthio)-5-mercapto-1,3,4-thiadiazole, 1-(4-n-hexylcarbamoylphenyl)-2-mercaptoimidazole, 3-acetylamino-4-methyl-5-mercapto-1,2,4-triazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercapto-6-nitro-1,3-benzoxazole, 1-(1-naphthyl)-5-mercaptotetrazole, 2-phenyl-5-mercapto-1,3,4-oxadiazole, 1-{3-(3-methylureide)phenyl}-5mercaptotetrazole, 1-(4-nitrophenyl)-5-mercaptotetrazole, 5-(2-ethylhexanoylamino)-2-mercaptobenzimidazole), substituted or unsubstituted mercaptoazaindenes (e.g., 6-methyl-4-mercapto-1,3,3a,7-tetrazaindene, 6-methyl-2-benzyl-4-mercapto-1,3,3a,7-tetrazaindene, 6-phenyl-4-mercaptotetrazaindene, 4,6-dimethyl-2-mercapto-1,3,3a,7tetrazaindene), substituted or unsubstituted mercaptopyrimidines (e.g., 2-mercaptopyrimidine, 2-mercapto-4-methyl-6-hydroxypyrimidine, 2-mercapto-4propylpyrimidine), heterocyclic compounds capable of forming imino silver compounds such as substituted or unsubstituted benzotriazoles (e.g., benzotriazole, 5-nitrobenzotriazole, 5 -methylbenzotriazole, 5,6-dichlorobenzotriazole, 5-bromobenzotriazole, 5-methoxybenzotriazole, 5-acetylaminobenzotriazole, 5-n-butylbenzotriazole, 5-nitro-6-chlorobenzotriazole, 5,6-dimethylbenzotriazole, 4,5,6,7-tetrachlorobenzotriazole), substituted or unsubstituted indazoles (e.g., indazole, 5-nitroindazole, 3-nitroindazole, 3-chloro-5-nitroindazole, 3- cyanoindazole, 3-n-butylcarbamoylindazole, 5-nitro-3-methanesulfonylindazole), substituted or unsubstituted benzimidazoles (e.g., 5-nitrobenzimidazole, 4-nitrobenzimidazole, 5,6-dichlorobenzmidazole, 5-cyano-6-chlorobenzimidazole, 5-trifluoromethyl-6-chlorobenzimidazole). The development inhibitor may be released from the redox nucleus of general formula (I) by a reaction following the redox reaction in the development step to become a development-inhibiting compound which may then turn into a compound having substantially no or remarkably reduced development inhibiting effect.
Specific examples of such a development inhibitor include 1-(3-phenoxycarbonylphenyl)-5-mercaptotetrazole, 1-(4-phenoxycarbonylphenyl)-5-mercaptotetrazole, 1-(3-maleinimidephenyl)5-mercaptotetrazole , 5-(phenoxycarbonyl)benzotriazole, 5-(p-cyanophenoxycarbonyl)benzotriazole, 2-phenoxycarbonylmethylthio-5-mercapto-1,3,4-thiadiazole, 5-nitro-3-phenoxycarbonylindazole, 5-phenoxycarbonyl-2-mercaptobenzimidazole, 5- (2, 3dichloropropyloxycarbonyl)benzotriazole, 5-benzyloxycarbonylbenzotriazole, 5-(butylcarbamoylmethoxycarbonyl)benzotr iazole, 5-(butoxycarbonylmethoxycarbonyl)benzotriazole, 1-(4-benzoyloxyphenyl)-5-mercaptotetrazole, 5-(2-methanesulfonylethoxycarbonyl)-2-mercaptobenzothiazole, 1-{4-(2-chloroethoxycarbonyl)phenyl}-2-mercaptoimidazole, 2-(3-{thiophene-2-ilcarbonyl}propyl)thio-5-mercapto-1,3,4-thiadiazole, 5-cinnamoylaminobenzotriazole, 1-(3-vinylcarbonylphenyl)-5-mercaptotetrazole, 5-succinimidemethylbenzotriazole, 2-{4-succinimidephenyl}-5-mercapto-1,3,4-oxadiazole, 3-{4-(benzo-1,2-isothiazole-3-oxo-1,1-dioxy-2-il)phenyl}-5-mercapto-4-meth yl-1,2,4-triazole, and 6-phenoxycarbonyl-2-mercaptobenzoxazole.
Examples of diffusive or nondiffusive dye, PUG include azo dyes, azomethine dyes, azopyrazolone dyes, indoaniline dyes, indophenol dyes, anthraquinone dyes, triarylmethane dyes, alizarin, nitro dyes, quinoline dyes, indigo dyes, and phthalocyanine dyes. Other examples of such dyes include leuco compounds of the above mentioned dyes, dyes whose absorption wavelengths have been temporarily shifted, and dye precursors such as tetrazolium salt. These dyes may form chelate dyes with proper metals. These dyes are further described in U.S. Pat. Nos. 3,880,658, 3,931,144, 3,932,380, 3,932,381, and 3,942,987.
Among these dyes, cyan, magenta and yellow dyes are important because they form color images.
Examples of yellow dyes include those described in U.S. Pat. Nos. 3,597,200, 3,309,199, 4,013,633, 4,245,028, 4,156,609, 4,139,383, 4,195,992, 4,148,641, 4,148,643, and 4,336,322, JP-A-51-114930 and 56-71072, and Research Disclosure 17630 (1978) and 16475 (1977). Examples of magenta dyes include those described in U.S. Pat. Nos. 3,453,107, 3,544,545, 3,932,380, 3,931,144, 3,932,308, 3,954,476, 4,233,237, 4,255,509, 4,250,246, 4,142,891, 4,207,104, and 4,287,292, and JP-A-52-106727, 53-23628, 55-36804, 56-73057, 56-71060, and 55-134. Examples of cyan dyes include those described in U.S. Pat. Nos. 3,482,972, 3,929,760, 4,013,635, 4,268,625, 4,171,220, 4,242,435, 4,142,891, 4,195,994, 4,147,544, and 4,148,642, British Patent 1,551,138, JP-A-54-99431, 52-8827, 53-47823, 53-143323, 54-99431, and 56-71061, European Patents (EPC) 53,037, and 53,040, and Research Disclosure 17,630 (1978) and 16,475 (1977).
One of the dye precursors can be a dye whose light absorption has been temporarily shifted in a light-sensitive element. Specific examples of such a dye are described in U.S. Pat. Nos. 4,310,612, T-999,003, 3,336,287, 3,579,334, and 3,982,946, British Patent 1,467,317, and JP-A-158638.
Examples of silver halide solvents represented by PUG include mesoionic compounds as disclosed in JP-A-60-163042, and U.S. Pat. Nos. 4,003,910, and 4,378,424, and mercaptoazoles or azolethiones containing an amino group as a substituent as disclosed in JP-A-57-202531. Specific examples of such silver halide solvents are described in JP-A-61-230135.
Examples of the nucleating agents represented by PUG include an eliminatable group portion to be released from couplers as described in JP-A-59-170840.
For PUG, reference can also be made to JP-A-61-230135, and 62-215272, and U.S. Pat. No. 4,248,962.
The compound represented by general formula (I) is preferably one represented by general formula (III): ##STR12## wherein EWG represents an electron-withdrawing group; m represents an integer from 1 to 5, and if m is 2 or more, the plurality of EWG groups may be the same or different; the phenyl group may contain from 0 to (5-m) substituents or be condensed with other aromatic rings, heterocyclic groups and nonaromatic rings and may be connected to B to form a ring or may be connected to a polymer residue to fix the compound of general formula (III) to a high molecular chain; A and B may be connected to each other to form a ring; and A, B, PUG, and n, the solid line, and the broken lines are as defined in formula (I), with the proviso that at least one of the plurality of the EWG groups is connected to the 2- or 4-position in the ring with respect to the oxygen atom.
Examples of EWG include a nitro group, a cyano group, a sufonyl group, a sulfamoyl group, a carbamoyl group, a carbonyl group, a halogen atom, and a trifluoromethyl group.
Furthermore, the compound represented by general formula (I) is preferably one represented by general formula (IV) or (V): ##STR13## wherein C, D, and E each represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkynyl group, an acyl group, a sulfonyl group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyloxy group, a sulfonyloxy group, an acylamino group or a sulfonylamino group which may be substituted or a polymer residue thereof or a group represented by general formula (VI) and may be the same or different and may be connected to each other to form a ring: ##STR14## ; A and B, and B and E may be connected to each other to form a ring; and PUG, A, B, n, the solid line, and the broken line are as defined in general formula (I).
The term "a polymer residue thereof" as used herein means that the groups defined as C, D and E may be present on the terminal of a polymer. Examples of the polymer include acrylic esters, metacrylic esters and acrylic amides.
Specific examples of the compound of general formula (I) are set forth below, but the present invention should not be construed as being limited thereto: